SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9488d4a55b6efee58e22d7da4d5aa4acdedf06cd078562049cd68adac057260' 
  AND token = 'pW0trkcqIYzc6fOaBjJKLstCtLrTlDObYWW55ew8U3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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