SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c169590999c45503533fc66f9359676683441afdc4cef1ef79ce0c815795e54' 
  AND token = 'mubgTZVDWWfTr4CVVL8d05ujiqtupa5Fc9WZ5SQzQpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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