SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '36686850d2cae7e2fed4301943c7416f6e5e246a048e054f87fc65f04ec95ea8' 
  AND token = '+lj+T8Leuzsb8bgbWYggCOcfrw3lljSiEzYbQjYDNro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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