SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4269fa9a40bce2e24d1d73f60621563d859ccdbd2790890bf262c086275bf084' 
  AND token = 'fzED49ZKHBhmSyiUh8tatmzg4sMl7xSZIBOpwI/GH+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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