SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad552f0be69d56f8fc0c7acb0fbfa9a5d96dae84bfc5afa0e2f3d8282674bfa5' 
  AND token = 'G++iSujbzZb3Q6nmf9nfbuzRvI3Beyq3NkOwrvn6NNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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