SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dbdf8f9d44268652065174f5b26ed7dd7a9c6e9eac5a02282d632b5d9c6f614' 
  AND token = '88z41o6nX+F+sqiKg4al+f952EN71iWCu608TJ3SZJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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