SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '637036b92bf07b81eda4759bfd521388d9bb2d434837bec309fbb6e0365fe42d' 
  AND token = 'qOmbSVASYgxWSltdTl8Fcvzi0cjiRIOFbmoSiYpr160=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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