SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '265368bba10f2b441560748691687f8a915239cf083940443d98a493b7e9b173' 
  AND token = '7A4NWysB9UyxHTfrYvzMJwg3IGFbh3BMUZcira9nKqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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