SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a830a6f873eaf5b276ebde076641e79ebe21f103d10c5b713aa1e82e80cb9105' 
  AND token = 'U/S9zVA4M9wOWkt6q9/2wjXQ3vjKm3cqu2WB5AHee8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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