SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e56bd99f8846e9b07462e56f83a259f4174b170389d3851abc8e44819bac99fc' 
  AND token = 'KSeXm6RuxCalm+c9fUMhDVQDi/KvDrp6grFVgUgJJHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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