SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af419ce7b19795c886b219576ef02bd288abd529b7ed3ebf375d1761f508b127' 
  AND token = '5REukud4kccxVc4a0hZdLFRouqFD8cAaCDgRJSj2fyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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