SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71a02432aa804a11ddd45723d125a6e8583918916a5aa26af6067049cb0747a9' 
  AND token = 'BadPhGH4CRktVO+v7OKd4WzGjhOV1093Rr1dzBBdTr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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