SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '10c36f1749ad3bdc7f65c909f1def79d33be7f2ca3c0322f493d3825f7cd4340' 
  AND token = 'Gx+sgXkg6Bc3JuFUuRn2dYrbv//aztGoDTWCwFoKl1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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