SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '015fc4d18f27e6f8fa7715ef07e328b4fd364dd7897179df4159d1d6a03ce7f8' 
  AND token = 'RJAkrnOTSocwIUshdrBq3qUly1a4gMIfUefDVuvpxR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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