SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7b1eaa7400d3f69150a75274bc69da618abfea2a947fc41808eef53ba452c3b' 
  AND token = 'C0sdFg1YVAFsXfGclrnxq/FTzFCUtGTv3sEudS4CyZ8=' 
  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"
    }
  }
}