SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8b8aaa5922fb8881bae755d9f1d5a34cfdd0059d9aba8c12fe828ac11ae8318' 
  AND token = '7y5yRlpj+bmBd49kMELMcV7rak9F/NGDvO/Poik1JnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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