SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '104b808a0fe3439a9512edc626181e6697c2a32c5b22d1e6dc299c20adf0d4b2' 
  AND token = '1zNVO6rlPgojX7mrpM1ZjQOd/p9v4XYhm5GKg4k+dJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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