SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b2bb046edef70d4da0bfdb18949294f90dfc39f539aa57eecd64fa3d7349154' 
  AND token = 'hBaFncyR6erEp3xKkwUupualpd8fuSlBcrvH9xLQX9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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