SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03e32c1ed415bdb0c9090b2c5478442c7acaa6f63a3f43385d6df51c66b851ee' 
  AND token = 'LwEm0UvcnglQ3NbyKIqTaXCZ9zYv7KG2v5gdGkMqMjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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