SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3ff51cf7cb6abeb6e3214fd9f19d6f4bc718d4a8d0b1b7dbe2805d9278afa325' 
  AND token = 'h5IZafVUbka19vaygSBn59N532w5QjUekygbFaMmkd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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