SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9875988ac759ef86e56d8ba89da7df5009481dfef63076a52a70d4572f923144' 
  AND token = 'aMoCyRnQvGqSZWc7RF/JtzV92ChkvpB1J0Gfy+c6Nx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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