SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b1ce9e20c6bd87415a39b2fe68a6539f4fa82bcacc46b2fee68a355b8b97a40' 
  AND token = 'iJ9OC8+jpA5NQsaQYsZ+YkPF02kJO7vpNNLHAsJ1iVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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