SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce9c4d4ec07e182591dd4fd2fe2af8fdc569b30e05fd48ba382b4a180dce0221' 
  AND token = 'z5OfVVoVpJ8bMHGmmmMnHX8liBDavGpwUYkWzfDqVHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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