SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '488c81a567031a7ad57d04cb342c3b7124d8a19d62f3a9bdeb983f981c443760' 
  AND token = 'grSI+ZNSnMWJYoVx3Kku9LbYqK4tRFqiQ/nOVwFJv6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}