SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a052953a7d9a764ba588916ebf3e444828e49d9fd6551677afa346983428b382' 
  AND token = 'ra9mcIwN4I3zw/qHyFmlPNj/oE3z++mx40sB1Zj/cQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}