SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c1010ba32dd43491e751de0b512c030ecb096decd4032f07baa48bf3c22d9f9' 
  AND token = 'qU6ltQUWoYDhIB+6MGp5FdqFR4OIEXSg55WerQ/Zovg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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