SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00953572e17cfa646071267efc98188d7e4df49d392267761a3dbf29412f112e' 
  AND token = 'SLBPPi1ey0bgDsh5kV+84qibLsJt3VP4hw3IjIZ2fI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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