SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8fe5ed23e72418505a8254a008afb0a9cc5e9727521f46c0af31ad2b950fc627' 
  AND token = 'S7ekCc5YxvEckcyZaciF3H5cMAthYnqBArFMImc6BzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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