SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dddfb960741370cda62e513a12186d4a927bacaffbd8f6ca8e57a0d7ac8a914b' 
  AND token = 'DM76RoFvbnXnUtyA1BODWVrWWYwgGSDjoaTH+zMJNOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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