SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f014746e0f6ac8cc23a8b6533b73491992a7f684f00f31e354f89a7d48831421' 
  AND token = '2YDe3AwiLVLFgWz8T+KHZUHkAjbDPntAmv5Wpe+nUcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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