SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbec00ecdaa0dbd700a364cab5370654bb3f1940f0313ed4ce8ea0a37b446417' 
  AND token = '1AKLP8iPfuLQ4NTHpv/NfXvyRr0j/t5NbEKRem/O6cI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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