SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5df4d7ae76f1a4b1c8f9216d0ef9f6f6257bdb1ff9d42a82c195dde7226b0688' 
  AND token = 'JgZKXHgHCIw+F93aeQjb9Ej+hD0p4jOOdWGr5bO3rWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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