SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96d512d731e6b2c940ce15dc36b14377a4bcbe452733388136f2fd6c3139b3c9' 
  AND token = '9193tPYCH8LlmkUVP/LfovoiUQJn9Y8DglYY+vu8Vks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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