SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94a0ea5e4ded6fe0ff5b57d7db5185ba8bfd669455479110b51d13a6fbf48a61' 
  AND token = 'rtND9+JgfL8bcNjJ58pAQ6zGUU1RQmU6xbyD8liOIa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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