SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3871f2d4a3d6d9dde7d96f2715f02e14a69f3afb334426a223ba53368cf92bb4' 
  AND token = 'rnd+Ji1qIxFqfg0iD2dBQnL97xmh632Fi5uOZL4U+K8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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