SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b619fd6bb2c66b7fa88735215c91a742f0537655777c38f57da3cff3cb17133' 
  AND token = '7/Nt7leqAbCwkbO3IhW8ma47IBRSk8F/zVPPTzQ8G6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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