SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c7c9bdb6a82d2c4d771e140a25c155c01a2d8a1295b9dbf604c6a2d13b3096d' 
  AND token = '54hv/XlOgkPFjF4iJrWASZmmlqXGmbW2aMUJpUzuKl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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