SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b1b13247e5b8436fb69af1cc81bc369267f482eda291aa1876691be4363ff927' 
  AND token = 'fDY6z0hkPsku30RL9PhOE7mTlbbshBLNsUoe3+88UKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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