SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f843c627a51859330c2909496757995596b9f13cc6fe6a5b93c44fec8c6bc295' 
  AND token = 'DK1TMQzL68lZFkNMSX/chuerwbCzRRM5ytornMrx4tY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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