SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '761117e19c4ca3d9bb6684552514550cc380ef076b57ca0aff38f8554d421910' 
  AND token = '9tuhHiF7erD+Lv6pjGMOFXE/Sp1PdMKUYZTvkbmC8v4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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