SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '553c8790d84bfde04ed2370c0684b3bb9a59840d5c8d6b1165e9af2416b93a82' 
  AND token = 'liLcvz2+GvRDzCghwEmAH2munKBtIGqZFyWsx3ls3ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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