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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d4635e724eb260a3c0937d75e9c8718f9dbfd5944e2c4fb81df6b6a0607ba9c' 
  AND token = 'z/zNW9NgiIHtBSyPVLC7a/L9cq6in1tomr/B1QUVyaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}