SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66dec3583576d64b05a04a10e3f797dad5ebd15d8bbeb712af95a59f0cb1512d' 
  AND token = 'qGpcLdJLauVg4OYafw9s6HGdSimJeuOsUqEJHo3biwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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