SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '834f15eb9e3eb0e569e5c5ba2c39787382aa8d6fb232a75d514e4baf5c8cec57' 
  AND token = 'CZCmAqERfGqsHP/OUezlEp+XuiHl4cGjAw8NIzDhtRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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