SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '331243cf037d648ef653ba6f8b3dd0ec995cf98b1eafc36c23b233a9d918d8ce' 
  AND token = 'kc7mn/CPnggPYhLopxPzGNmyIVZVVtDnmDJ7CoTY6VQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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