SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b1bb54dc13208889525383402cd705a690d0cafac6568b1a2df494878b06795' 
  AND token = 'mPNvqDRTp7SDFGOspdER+BBlX70Dzo5jmGkBvTK25I8=' 
  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"
    }
  }
}