SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a12c52f7277459f4e905944f685889cda1bf1a476ac327f8d607143a34418c8' 
  AND token = 'D/NFbzrbYquyzU/Thq5QhIIhXu8z35BvkMLhCnPG6JI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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