SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdba5087a9b6971d1d14ffef7865fe1eb2388b0088a41b6a348b3f8f13044a4f' 
  AND token = 'PC8AKUiKF3+eUJxz1Aiq1uiLbGa2ZIKDiiH/3I/rKMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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