SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5ab83e903fba388fbbd18e692bba4ddbf830d6d4b87876258e9ba0f1e214d70' 
  AND token = 'vz2ZZOaAWaWECLlkK+nNH5ljXHJDVA9sB09/gb6vvwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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