SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcfc6fca8b32958d408907808fef80e0cd81ba686897ad3aaba216feeed243c3' 
  AND token = 'FLHrOpQjU4QJ/C+PljZyJBqdByyUBX5cwjgwFAcMBUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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