SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a828dcff5c4cbabac2d3231c42f8455662c2cef2738192cb86552948eb6efb21' 
  AND token = 'bqljhrqawNCeeso9CnCAcQl6M5cBIgH4RN2wBS2Cxi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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