SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a85def7d7fcb1909eb3596ab14b4c7df518eb5a83fb8492fe9261851f4570fbe' 
  AND token = 'aPXFPyvqTCZ/+TzOmzfNP9y6SK9/Ho98Zkq0N333WQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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