SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '795d31d8c129c5afb1ba72aa95d41dac6826cd69e51d7cd2f1b7e068f22a8b0f' 
  AND token = 'Yq6wihZc+c6Lj2WVZVMvXyF67OwqxdQZ0FXKigoOPms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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