SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14012ccef20e33764886f735f74b5ae8e48caab399ade13e73820ac15785199b' 
  AND token = 'dC2k1msEMVrtwtwgBWpmXOrBNDknZIQ4qLgC9nJUJPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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