SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '918c92a2ee51853dc21b98ee7b3ad402630c12d1478c2aa1d6c26f5a2247f2f3' 
  AND token = 'qtyHxp6IoITX1zPZNNCU3NRQLIMWMnWk43w57HgGeZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}