SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81eb9f77bdfb5b16aafc6ad0b604c5570def54496040cc6bec0c50555dbd1567' 
  AND token = 'md+d+v0zEJbPjhsQypYXnTL12Uyb+VV62wKNENlvF28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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