SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a123f30bf2757cbdfff6681ca5657ec4b5e9d7a88114170c79423eedb0d69d0' 
  AND token = 'hIspkKssRaKnZgwYZKCxOmhmYZapy2++hK/brIbLWbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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