SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f835b66f6d8baf578f8a09d97bd25f421b3dc8c577a1e0d74d9b2b9822d72b76' 
  AND token = 'cL4I7hH/z4hpgl4DQYK+nHL1lp2O9tNxAe7qZdjQN8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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