SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a6d48bd6bcc9aadc188f8fb2f77a0f06863635f5830478ea3f274489f8a5c01' 
  AND token = '/m7uCms/CcmJ0pKd2IDMhLG9DqJRWMCHwV+xQPUI9/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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