SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c12c725223181c68395bed23bb58300b4da2368ccf202d210e722da44c14c542' 
  AND token = '742gsxs4wCjD5qmGMpIyFPrBztUA6Uoh2TYfuKPHujo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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