SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '931a090b675b33ea52646c70d41205abbcbd87503de3e5bc06ff6a88113508aa' 
  AND token = 'rHaatqryGTk+9+bTco42GMJgEG4wLXgHr9wsMuKy+A4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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