SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edbce289e650d8f72e6ff6820759626b8ead0083d0f92a1a7e33a915937a5a37' 
  AND token = 'mOqLSxhAQ45nGn7hStZxqtOEaAseMB6tym0/W0PP3vY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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