SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7d87eadd436f04491a38129b45b39291a1006d1834ef7a4ebdf746a2ca9bf7d' 
  AND token = '5+/cGMvmYkKGUoohpzzvFYqVDWmYyJrUSEG+BXUqH/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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