SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b62d659e306fdee87c54dff35d03553e4e410501bd77ee7d0fcdc72a1d29567a' 
  AND token = '2tJkY21Lk6qKRC/wjHPZtLP6qp1Cgf1IlHZQ9uYGBok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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