SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8fbc95d2c143da5b1690957b77acf2003921e628b71a5bad8069e88cdf6c4d3' 
  AND token = 'WIrEWnGCRQ4BqydIjxWcv/wQg70IeLRlP5wWl/ELL7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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