SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef88d371ba7fa07cb3879f7a23b454eb378e2f2e3e54a55b71b42230764e4d1d' 
  AND token = 'xNrKvQIIuiMwRJEYeXGw/ufZHDFjXwoTXl86m5yz5WU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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