SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a41cdae76a2b58a55902cf9b9bb659caa36e0b4fd0c31a76a49f577985a0d05' 
  AND token = 'r9EWMoB8cijHMx492UsONqWiiVAbDCnoAo0eK+fjbiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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