SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fc1ff97102858a343f326febde6a613ff0a59746b772e7a00925ef32561e1cac' 
  AND token = 'ZXcAOWggiJOSH4Muix6ynpfQqQ/aysa1ZsXBawpgWuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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