SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b9520acfb5026456bb530a7e87af0b2cdf5be324bcde18d6e79db144fd957db' 
  AND token = 'MgpZnhtwuNlgC7EWjLBrB7Ny7kmrak+HGwZoLnpVW20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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