SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97e8eb6ce2b9dccf961780941ca23d6934a84a02efff2d863ff24c355a5f5f39' 
  AND token = 's8hNXLyBKLrMORzyyKuvcmggtraBoiDnNmdQi4vSSIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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