SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be38f821b7cc3833c0dd044bcf1bf8a836c1f8b5d0e42bf401f87c0872b7f94e' 
  AND token = '1v5GCwojggCKworDPeTCZA+lXrv/RVoHUPpfq5vAMjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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